To assess the changes in treatment and outcome of acute myocardial infarction (AMI) over a 15-year period, the medical records of 1,437 patients with AMI who underwent emergency coronary angiography within 24h of the onset of chest pain at Hiroshima City Hospital from 1985 to 1999 were reviewed. The patients were divided into 3 groups in chronological order: group 1 (1985-89, n=439), group 2 (1990-94, n=453) and group 3 (1995-99, n=545). Conventional balloon angioplasty and thrombolysis were frequently performed in group 1 (56% and 29%, respectively) and group 2 (71% and 13%, respectively), whereas coronary stenting and conventional balloon angioplasty were more often performed in group 3 (57% and 23%, respectively). The achievement of TIMI grade 3 flow improved in the chronological order (62%, 80% and 85%, respectively; p<0.001). The incidence of reinfarction was lower in group 3 (4.2%) than groups 1 and 2 (8.0% and 7.5%, respectively; p=0.007), and in-hospital mortality decreased from group 1 to group 3 (11.8%, 8.2% and 5.5%, respectively; p=0.002). Stenting is now the most frequently chosen treatment for AMI and sustained TIMI grade 3 flow is obtained in most of the cases, with the result that mortality has reduced by 50% in the past decade.